Found the following HTML validation problems:
col_count_match.html:367:1: Warning: <img> lacks "alt" attribute


col_exists.html:311:1: Warning: <img> lacks "alt" attribute


col_is_character.html:312:1: Warning: <img> lacks "alt" attribute


col_is_date.html:311:1: Warning: <img> lacks "alt" attribute


col_is_factor.html:317:1: Warning: <img> lacks "alt" attribute


col_is_integer.html:310:1: Warning: <img> lacks "alt" attribute


col_is_logical.html:312:1: Warning: <img> lacks "alt" attribute


col_is_numeric.html:312:1: Warning: <img> lacks "alt" attribute


col_is_posix.html:312:1: Warning: <img> lacks "alt" attribute


col_schema_match.html:393:1: Warning: <img> lacks "alt" attribute


col_vals_between.html:469:1: Warning: <img> lacks "alt" attribute


col_vals_decreasing.html:465:1: Warning: <img> lacks "alt" attribute


col_vals_equal.html:434:1: Warning: <img> lacks "alt" attribute


col_vals_expr.html:381:1: Warning: <img> lacks "alt" attribute


col_vals_gt.html:435:1: Warning: <img> lacks "alt" attribute


col_vals_gte.html:434:1: Warning: <img> lacks "alt" attribute


col_vals_in_set.html:411:1: Warning: <img> lacks "alt" attribute


col_vals_increasing.html:453:1: Warning: <img> lacks "alt" attribute


col_vals_lt.html:435:1: Warning: <img> lacks "alt" attribute


col_vals_lte.html:436:1: Warning: <img> lacks "alt" attribute


col_vals_make_set.html:421:1: Warning: <img> lacks "alt" attribute


col_vals_make_subset.html:418:1: Warning: <img> lacks "alt" attribute


col_vals_not_between.html:465:1: Warning: <img> lacks "alt" attribute


col_vals_not_equal.html:433:1: Warning: <img> lacks "alt" attribute


col_vals_not_in_set.html:398:1: Warning: <img> lacks "alt" attribute


col_vals_not_null.html:393:1: Warning: <img> lacks "alt" attribute


col_vals_null.html:392:1: Warning: <img> lacks "alt" attribute


col_vals_regex.html:435:1: Warning: <img> lacks "alt" attribute


col_vals_within_spec.html:498:1: Warning: <img> lacks "alt" attribute


conjointly.html:389:1: Warning: <img> lacks "alt" attribute


create_agent.html:463:1: Warning: <img> lacks "alt" attribute


create_agent.html:480:1: Warning: <img> lacks "alt" attribute


create_informant.html:298:1: Warning: <img> lacks "alt" attribute


create_informant.html:314:1: Warning: <img> lacks "alt" attribute


create_multiagent.html:160:1: Warning: <img> lacks "alt" attribute


draft_validation.html:346:1: Warning: <img> lacks "alt" attribute


email_create.html:100:1: Warning: <img> lacks "alt" attribute


file_tbl.html:188:1: Warning: <img> lacks "alt" attribute


get_agent_report.html:296:1: Warning: <img> lacks "alt" attribute


get_agent_report.html:320:1: Warning: <img> lacks "alt" attribute


get_agent_report.html:333:1: Warning: <img> lacks "alt" attribute


get_multiagent_report.html:291:1: Warning: <img> lacks "alt" attribute


incorporate.html:127:1: Warning: <img> lacks "alt" attribute


incorporate.html:151:1: Warning: <img> lacks "alt" attribute


info_columns.html:245:1: Warning: <img> lacks "alt" attribute


info_columns_from_tbl.html:132:1: Warning: <img> lacks "alt" attribute


info_columns_from_tbl.html:161:1: Warning: <img> lacks "alt" attribute


info_section.html:222:1: Warning: <img> lacks "alt" attribute


info_snippet.html:190:1: Warning: <img> lacks "alt" attribute


info_snippet.html:209:1: Warning: <img> lacks "alt" attribute


info_tabular.html:205:1: Warning: <img> lacks "alt" attribute


interrogate.html:135:1: Warning: <img> lacks "alt" attribute


log4r_step.html:171:1: Warning: <img> lacks "alt" attribute


row_count_match.html:424:1: Warning: <img> lacks "alt" attribute


rows_complete.html:383:1: Warning: <img> lacks "alt" attribute


rows_distinct.html:384:1: Warning: <img> lacks "alt" attribute


scan_data.html:133:1: Warning: <img> lacks "alt" attribute


serially.html:424:1: Warning: <img> lacks "alt" attribute


serially.html:445:1: Warning: <img> lacks "alt" attribute


snip_highest.html:81:1: Warning: <img> lacks "alt" attribute


snip_list.html:157:1: Warning: <img> lacks "alt" attribute


snip_lowest.html:81:1: Warning: <img> lacks "alt" attribute


snip_stats.html:104:1: Warning: <img> lacks "alt" attribute


specially.html:294:1: Warning: <img> lacks "alt" attribute


tbl_match.html:362:1: Warning: <img> lacks "alt" attribute


tbl_source.html:99:1: Warning: <img> lacks "alt" attribute


tt_summary_stats.html:196:1: Warning: <img> lacks "alt" attribute


yaml_agent_interrogate.html:82:1: Warning: <img> lacks "alt" attribute


yaml_agent_interrogate.html:112:1: Warning: <img> lacks "alt" attribute


yaml_agent_show_exprs.html:96:1: Warning: <img> lacks "alt" attribute


yaml_informant_incorporate.html:86:1: Warning: <img> lacks "alt" attribute


yaml_read_agent.html:88:1: Warning: <img> lacks "alt" attribute


yaml_read_agent.html:118:1: Warning: <img> lacks "alt" attribute


yaml_read_informant.html:79:1: Warning: <img> lacks "alt" attribute


yaml_write.html:239:1: Warning: <img> lacks "alt" attribute


yaml_write.html:269:1: Warning: <img> lacks "alt" attribute


yaml_write.html:372:1: Warning: <img> lacks "alt" attribute